Bio-chemotherapeutic strategies and the (dis) utility of hypoxic perfusion of liver, abdomen and pelvis using balloon catheter techniques

Locoregional intravascular viral therapy of cancer: precision guidance for Paris's arrow?

Viral therapy of cancer includes strategies such as viral transduction of tumour cells with 'suicide genes', using viral infection to trigger immune-mediated tumour cell death and using oncolytic viruses for their direct anti-tumour action. However, problems still remain in terms of adequate viral delivery to tumours. A role is also emerging for single-organ isolation and perfusion. Having begun with the advent of isolated limb perfusion for extremity malignancy, experimental systems have been developed for the perfusion of other organs, particularly the liver, kidneys and lungs. These are beginning to be adopted into clinical treatment pathways. The combination of these two modalities is potentially significant. Locoregional perfusion increases the exposure of tumour cells to viral agents. In addition, the avoidance of systemic elimination through the immune and reticulo-endothelial systems should provide a mechanism for increased transduction/infection of target cells. The translation of laboratory research to clinical practice would occur within the context of perfusion programmes, which are already established in the clinic. Many of these programmes include the use of vasoactive cytokines such as tumour necrosis factor-alpha, which may have an effect on viral uptake. Evidence of activation of specific anti-tumour immunological responses by intratumoural and other existing methods of viral administration raises the intriguing possibility of a locoregional therapy, with the ability to affect distant sites of disease. In this review, we examined the state of the literature in this area and summarized current findings before indicating likely areas of continuing interest.

Laboratory models of regional chemotherapy

Development of new treatment strategies and agents is a difficult and costly matter in oncology. Routinely drugs are tested in vitro on tumor cells which, however, may have limited predictive value for their activity in patients. Also, the pharmacokinetic behavior, intratumoral distribution, as well as toxic side effects, binding to other compounds and stability of an agent are very important in determining activity in the patient. More so, development and evaluation of surgical delivery methods, i.e. regional treatment strategies, cannot be tested in cell systems. Therefore animal models are crucial for the development of regional chemotherapy methodologies. To allow translation of the animal data to patients it is important that the animal model closely mimics the clinical setting as for instance is achieved with isolated limb perfusion. However, animal models remain limited in their use, as eventually the efficacy of the approach may be different in animals compared to patients. Here we describe the use of animal models for regional treatment of solid tumors.

Pressure-suit combined with pelvic stop-flow: A feasibility study in a bovine model

BACKGROUND

Isolated pelvic perfusion exposes tissue to high drug doses and may benefit patients with advanced malignancy. However, leakage is a limit to this technique.

AIMS

The aim of the study is to increase the perfusion ratio between local and systemic compartments on isolated pelvic perfusion. We hypothesised that an inflated pressure-suit placed above the level of aortic and caval stop flow could decrease leakage from the regional to the systemic blood compartment in a bovine model.

METHOD

As the size of the pressure-suit was adapted for use in humans, we performed our experimental study on 6 calves which are big enough to fit into the suit. We used an inflated pressure-suit placed at low (40mmHg) and high pressures (125mmHg) above the level of aortic and caval stop-flow. A pharmacokinetic study with cisplatinum was performed in both compartments.

RESULTS

After injection of the drug, the mean ratio of drug concentration in the locoregional/systemic compartment was 43.1. After 30min, this mean ratio was 4 and 9.7 for a pressure-suit pressure of 40mmHg and 125mmHg, respectively. At pressure-suit pressures of 40mmHg and 125mmHg, pelvic perfusion achieved pelvic/systemic exposure ratios of 5.9 and 14.9 at 30min, respectively. Leakage at 30min was higher when the pressure-suit was inflated at low pressure (40mmHg, mean 18%). When the pressure-suit was inflated at high pressure, leakage was lower (125mmHg, mean 7%).

CONCLUSIONS

The pressure-suit increased the perfusion ratio between pelvic and systemic compartments in a bovine model.